Steel retainer



April 14, 1942. E. F. TERRY STEEL RETAINER Filed Oct. 14, 1939l INVENTOR HIS ATTORNEY Patented Apr. 14, 1942 STEEL RETAINER Edward F. Terry, Phillipsburg, N. J., assignor to Ingersoll-Itand Company, New York, N. Y., a corporation of New Jersey Application October 14, 1939, Serial No. 299,402

4 Claims.

This invention relates to rock drills, and more particularly to a retainer for preventing ejection of a working implement from a rock drill of the type in which the working implement and the percussive element actuating it are capable of reciprocatory movement independently of each other.

One object of the invention is to equip the rock drill with a retainer of simplified and rugged construction and which will permit of the working implement being 'expeditiously inserted into and removed from the rock drill.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing accompanying this specification and in which similar reference numerals refer to similar parts,

Figure 1 is an elevation, partly in section, of the front end portion of a rock drill equipped with a retainer constructed in accordance with the practice of the invention,

Figure 2 is a transverse view taken through Figure 1 on the line 2-2, and

Figure 3 is a perspective view of the retainer.

Referring more particularly to the drawing, 29 designates, in general, a rock drill of which only a front head 2| and a portion of a cylinder 22 are shown as casing parts.

The front head 2| and the cylinder 22 may be secured together in any well known manner, and in the front head 2| is a cavity 23 into which the nose of the hammer piston 24, reciprocable in the cylinder 22, moves for delivering blows to a working implement 25 extending through the front head 2| and terminating in the cavity The bcre 26 in the front head 2| through which the working implement 25 extends is only sufiiciently larger than the working implement to permit of free slidable movement of the latter, and in one side of the front head 2| and opening into the bore 26 is an aperture 21 to receive a retainer 28 constructed in accordance with the practice of the invention. The aperture 21 is of oblong cross sectional form, having upper and lower semi-cylindrical surfaces 29 which are joined by fiatted surfaces 30 tangent thereto.

The aperture which extends from one side to the other of the front head 2| is preferably of uniform cross sectional area throughout its length and is so located that the innermost surface 39 lies closely adjacent the plane of a flat surface 3| constituting the bottom of a recess 32 extending longitudinally of the working implement 25 and being rounded at its ends to form Shoulders 33 and 34 at the upper and lower ends, respectively, of the recess. The retainer 28 is of substantially the same cross sectional form as the aperture 21 and is of greater length than the aperture so that its ends project beyond the sides of the front head. It comprises, in the form illustrated, a pair of rigid plates 35 and 36 each having a fiat outer surface 31 to seat against a surface 30 of the aperture, and at the ends of the flat surface 31 are rounded surfaces 38 to conform substantially with the curvature of the surfaces 29 of the aperture, and with the shoulders 33 and 34 for which they serve as abutments. I

To the end that the retainer may be rendered contractible and expansible in a lateral direction a strip 39 of resilient material, preferably rubber, is interposed between the plates 35 and 36,

and suitably bonded to the inner surfaces of o the plates to form a unitary structure. The combined thicknesses of the plates 35 and 36 and the rubber strip 39 is somewhat greater than the distance between the fiat surfaces 30 of the aperture 21. Thus, when driving the retainer into the aperture the plates may move toward each other as by displacing the rubber which will press the plates outwardly against the flat surfaces 39 and in that way maintain the retainer in firm frictional engagement with the front head.

Preferably the plate 36 is provided with a lateral Wing which overlies an end of the strip 39 in the plate 35 and may serve as a stop member for engagement with the side of the front head to prevent the retainer from being placed in an incorrect position in the aperture. Moreover, for the sake of convenience in placing the retainer in the aperture the opposite end 4| of the retainer is bevelled fora short distance to enable it to readily enter the aperture 21.

In practice, the present invention has been found to serve in a highly efiicient manner as a retainer for preventing ejection of a working implement from a front head. The retainer may be expeditiously inserted in the retaining position or removed from the front head and when in the retaining position will be held firmly thus by the force of the rubber strip 39 which, being distorted somewhat when inserted into the aperture, will tend to resume its normal form and thereby press the outer surfaces of the plates 35 and 36 against the surfaces of the aperture21.

A further highly' desirable advantage of a retainer constructed in the manner described is sectional form in the front head, a retainer in v the aperture comprising a plurality ofwrigidl'.l members either of which may serve as an abut-h ment for the shoulder, and a resilient memberbetween the rigicl memberfor maintaining the for the shoulder and comprising alternately arranged strips of rigid and resilient material.

3. A steel retainer for a rock drill having a front head to receive a working implement having aV shoulder, an aperture of oblong crosssectional form in the front head, a retainer in the aperture comprising a plurality of rigid members either of which, may serve as an abutment Vfor the shoulder, and a resilient member between and bonded to the rigd' members to mamtain the retainer in frictional engagement with the 'Wall of the aperture. v

' 4. A`stee1 retainer for a rock drill having a front head to receive a working implement havrigid members in frictional engagement with the wall of the aperture.

2. A steel retainer for a rock drill having a front head to receive a working implen'ent having a shoulder, an aperture of oblong crosssectional form inthe front head, and a retainer in the aperture having a plurality of rounded surfaces each adapted to serve asV an abutment ing a shoulder; an aperture of oblong cross- .sectional form in the front head, and a retainer of greater width than the aperture to lie in said aperturev forwardly of the shoulder and having an intermediate resilient zone to permit of lateral contraction and expansion of the retainer, said retainer having a plurality of rounded surfaces each adapted to serve as an abutment for the shoulder.

i EDWAPMD F. TERRY. 

